Ability to configure keywords on Ideas to improve discoverability in portal

When stakeholders are using an Ideas portal they are searching for a term they are familiar with, and this may not have been used on an idea they are actually searching for. In our industry an example would be searching for "Taxes" and not locating an idea that only ever mentions 1099 forms. What would be helpful is if we could, within Aha!, tag ideas with keywords that would help with discoverability.

Alternatively using categories could support this, but the list of keywords would be extensive and would cause clutter within the category filters. The Tags field as another alternative would be feasible, but exposing the keywords to stakeholders could be nice, and tags has internal and external usage.